Write all the help text for the util-linux utilities. Allow

people to locate the mtab file somewhere other that /etc to
accomodate read only root filesystems.
 -Erik

libbb/mtab_file.c

@@ -26,7 +26,7 @@
 /* Busybox mount uses either /proc/mounts or /etc/mtab to 
  * get the list of currently mounted filesystems */ 
 #if defined CONFIG_FEATURE_MTAB_SUPPORT
-const char mtab_file[] = "/etc/mtab";
+const char mtab_file[] = CONFIG_FEATURE_MTAB_FILENAME;
 #else
 const char mtab_file[] = "/proc/mounts";
 #endif